1. Field of the Invention
The present invention relates to an air cleaning apparatus arranged within an air conditioner, an air cleaner, or the like, and more particularly to an apparatus and method for controlling air cleaning, which is capable of cleaning air by controlling an AC voltage or an AC frequency therein, depending on the pollution level of indoor air.
2. Description of the Related Art
An air cleaning apparatus generates a number of negative ions using an air cleaning element, and thereby cleans indoor air using such generated negative ions, wherein the air cleaning element is referred to as a negative ion generator of a surface discharge type which has recently been developed.
FIG. 1 is a block diagram showing the construction of a conventional air cleaning control apparatus, and FIG. 2 is a graph illustrating an operating control state of the conventional air cleaning control apparatus. Referring to FIGS. 1 and 2, the conventional air cleaning control apparatus using the above air cleaning element will be explained as follows.
The conventional air cleaning control apparatus includes, as shown in FIG. 1, a rectifier 3, a DC voltage generator 5, an air cleaning element 7 and a microcomputer 9. The rectifier 3 rectifies an AC voltage into a DC voltage, for example, it may rectify a commercial AC voltage of 220V into a 12V DC voltage. When the 12V DC voltage is supplied to the DC voltage generator 5, the DC voltage generator 5 supplies a high voltage to the air cleaning element 7 so as to generate negative ions.
As shown in FIG. 2, the microcomputer 9 generates ON/OFF signals in response to an operation signal and a stop signal manually inputted by a user, wherein the ON signal is converted into a high-voltage signal by the DC voltage generator 5, and the OFF signal is converted into a ground voltage signal by the DC voltage generator 5. Thus, any one of the high-voltage ON signal and the ground OFF signal is applied to the air cleaning element 7.
For example, when the microcomputer 9 supplies the ON signal to the DC voltage generator 5, the high-voltage ON signal is generated by the DC voltage generator 5. In addition, the high-voltage ON signal is applied to the air cleaning element 7, thereby generating negative ions by means of plasma discharge in the air cleaning element 7.
The negative ions generated in the air cleaning element 7 are supplied to indoor air passing through the vicinity of the vicinity of the air cleaning element 7, thereby cleaning indoor air.
However, the above conventional air cleaning control apparatus has a structure for merely generating the negative ions and cleaning indoor air, without regard to a state of indoor air. Even when indoor air is relatively seriously polluted by some contaminants such as cigarette smoke, dust, etc., the air cleaning element 7 operates uniformly without regard to a pollution state. Thus, because the air cleaning element 7 does not operate in correspondence with the pollution level of indoor air, it does not effectively clean indoor air.
Particularly, the above conventional air cleaning control apparatus has the DC high-voltage generator 5, but it is not possible to easily control characteristics of the DC high-voltage generator 5. For this reason, even though the DC high-voltage generator 5 is used, it is difficult to easily generate ozone below a predetermined limit value using the air cleaning element 7. Consequently, even though ozone has a high sterilization effect, because ozone is not easily generated below the predetermined limit value, it is difficult to sterilize and clean indoor air.